<DKIM> Emails might go to GMail's SPAM folder

[Raphaël]

This is DMarc related (specifically Laposte.net DKIM policy)
Headers show that Gmail failed on DMarc verification, more specifically
on body verification.
And it follows Laposte.net DMARC policy which states "quarantine" for
emails which fail the test.

> DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=laposte.net;
> s=mail1; t=1453800265; bh=RDxy8MXcKKYU0BSroNAGNtx/JLJ9xAe/ZEuDT5GKkXI=;
> h=Date:From:To:Cc:Subject:References:In-Reply-To;
> b=[...base64...]

+ `dig _dmarc.laposte.net. TXT`


Laposte.net asks the receiver to put in quarantine emails failing tests
about headers (Date, From, ...) and *BODY* too.

But my guess is that intermediary mailing-list daemons add a footer
which change the body what makes test fail.

Laposte.net should probably avoid "b=" and "bh=" DKIM fields which are
unsuitable for mailing-list consumption where email body (esp. footer)
modifications are to be expected. Checking a couple of headers seems an
acceptable trade-off.


Side note : individually marking non-spam is very unlikely to work.
GMail will always follow DMarc hints since that's what they are for.
Laposte says emails whose body do not match signature (= body modified)
"should" (or "must" ?) be put in quarantine.  
For once GMail SMTP/IMAP stack respects an email RFC, let them this one.



On Tue, Jan 26, 2016 at 10:24:24AM +0100, Nicolas Sebrecht wrote:
> On Tue, Jan 26, 2016 at 09:43:02AM +0800, Oon-Ee Ng wrote:
> 
> > Nicolas, you probably already know this but the 'reason' I'm given
> > is:- It has a from address in laposte.net but has failed laposte.net's
> > required tests for authentication.
> 
> True. Sadly, there's nothing I can do about that.
> 
> > Unlikely to be very useful, but may as well put it out here. I'm
> > marking as 'not spam', I think if enough people do that you get
> > whitelisted (no idea how Google's filters works).
> 
> Right. I'm giving a fixed-once option.
> 
> Marking each mail as non-spam is another alternative that may work.  We
> don't know Gmail's rules so the only way to check is to try. Or, ask to
> Gmail's support.